Synthetic mineral compositions are well known. U.S. Pat. No. 4,433,070 to Ross and Stevens first disclosed such compositions having the advantage of polishability by virtue of using a resinous filler in a resin matrix of like hardness, rather than the then common inorganic fillers which were difficult to distribute properly and adversely affected polishing qualities. Other patents have disclosed conventional systems of acrylic resin with various fillers as synthetic mineral simulative compositions, e.g. U.S. Pat. No. 3,663,493 to Miller, and patents therein described, and U.S. Pat. Nos. 4,085,246 and 4,159,301 both to Buser et al which disclose in addition to acrylic resin matricies a variety of other polymers, including polyesters, which are filled with a blend of microscopic fillers and macroscopic translucent or transparent particles for an asserted granite effect. Brit. No. 1,174,952 to Majnoni disclosed buttons formed of polyester matrix and polyester scrap solids to produce what can be described as a variegated effect.
Other patents in the field include those to Duggins: U.S. Pat. Nos. 3,827,933 and 3,847,865 which teach filled acrylic polymers particularly, and containing alumina trihydrate. In the Duggins patents it is pointed out that the use of alumina trihydrate filler as a flame retardant in polyester resins was taught in a Connolly and Thornton article in Modern Plastics 43, 154 (1965).
Neglected in the development of the art has been the combining of flame retardancy with polishability. Hitherto disclosed compositions have had either the polishability of the Ross and Stevens product, or the flame retardancy of the acrylic products, but not both in one product.